Madlax — The Firstari, the Secondari and the Thirstari are capable of driving cities of men into their darkest emotions, creating doppelgangers, and bringing down airplanes.
Common item in the Read or Die TV series done different ways. One example had a god-like man named "The Gentleman" who had his essence written into a number of such books. In the OVA series, there's a subversion: handwritten notes in the margins of an otherwise-harmless book held the secret to driving the entire human race to suicide. The manga used it straight; The Dark Abyss, a book bound in human flesh, that the publisher required 5 different people to print, a page at a time. Reading it or listening to someone read it instantly resulted in insanity.
YuYu Hakusho has a videotape, Chapter Black, which serves essentially the same purpose. It's a recording of every evil deed ever done by humans, which human-hating Big Bad Sensui makes a point of showing to his followers to drive them insane with disgust at people.
Notably, it's part of a two-tape set. The other tape, Chapter White, records every good deed ever done by humans, and you're not supposed to watch one without the other. Guess what Sensui did.
Soul Eater has the Book of Eibon, written by a sorcerer centuries ago. It contains the information Arachne used to create the original Demon Weapons, and to turn herself into a psuedo-Kishin. It is currently being used by Noah, who impersonated Eibon, to collect anything he sees as interesting. Such as Death the Kid.
Which is a shout-out to the fictional tome (aka the Liber Ivonis) from the Cthulhu Mythos(see below).
The book itself is so evil that it's indexed by sins, and it currently contains at least one of the worst creatures imaginable, Excalibur. Oh, and there's a Great Old One who bears a striking resemblance to Cthulhu.
And later we learn that Noah is actually a construct of the book itself, embodying one of it's chapters, not it's owner. After the first one (Greed) is defeated, the book produces a new one - embodiment of chapter of Wrath.
The Book of Darkness in Magical Girl Lyrical Nanoha A's. It managed to open itself despite being chained shut. To power it up, you have to collect the magic power of other people and creatures; if you decline to, it will drain your power instead, slowly killing you. And when all its pages (naturally, there are six hundred and sixty-six of them) are filled, do you think you can wield its power? You're as good as dead, and so is the planet you are on. (The tragedy is that it wasn't originally that way - it has been corrupted by people who wanted to use it as a weapon.)
The Claire Bible in Slayers. Its author is benign enough (one of the good dragon-gods of the Slayers world), but its subject is the Mazoku race and the dragons' war with them, with extra details on the Mazoku-powered black magic and the secret magic of the supreme creator deity. The genuine Claire Bible is also not a book, but a sphere holding infinite knowledge, however many fragments of it are indeed scribed as books and scrolls.
In NEXT, the heroes suspect every strange magical effect they hear of to be caused by a Claire Bible manuscript, indicating that even the mundane fragmentary copies can have weird properties.
The Black Bible from Bible Black, replete with demonic rituals. You really don't want to be in the building when this thing gets used. Every major spell requires a Human Sacrifice, and even the minor ones tend to cause cases of Demonic Possession.
The Books of Zeref in Fairy Tail. Black Mage Zeref wrote a bunch of books infused with magic that allows people to accomplish truly awesome and terrifying feats, such as demon summoning and time travel. Each Book contains the rituals and magic necessary to summon a different demon.
Possibly the ultimate form of this trope is Destiny of The Endless's Book. In it is written the entirety of existence, past , present and future. Every person, every bit of knowledge, every event, every possibility. It's a good thing the Book is chained to Destiny and he's the only one who can read it, cause anyone else reading it would either grow omnipotent or have his/her mind irrevocably shattered.
Destiny has given the book up after a group were able to venture outside of destiny essentially "screwing it up."
In an episode of The Badger dealing with Lovecraftian beasties, Mavis whipped out her "Pocket Necronomicon".
In the Marvel Universe, a Tome called the Darkhold contains a variety of spells, including the Montessi Formula, which unmakes vampirism (and vampires).
Worth mentioning, that using any spell from this tome equals sealing your soul to evil god Chthon, and most of them works in really twisted and sick ways.
One of the weird things about it is that in the MU, vampirism started when a group of Atlantean sorcerers slew their enemies, but weren't satisfied with simply winning the fight and killing their foes. They wanted to make them suffer after death, so they used a spell from the Darkhold to raise them as the first vampires. Predictably things after that did not go 'quite' as the sorcerers intended.
There is also the Book of the Vishanti which is said to contain every counterspell and defensive magic ever known or will be known, including a spell to free one from the Darkhold's control (odd that it doesn't seem to contain the spell to cure vampirism, which is in the Darkhold). It also contains a lot of useful lore penned by previous holders of the tome and it seems to explicitly add new pages for current owners to add their own information into its pages.
Kurt Busiek's The Wizard's Tale revolves around a Tome of Eldritch Lore which the inept and not particularly evil wizard must locate and cast spells from. Fortunately, he learns that the good guys hid it rather than destroyed it because it contains a spell to banish evil. He casts it instead.
The Sinestro Corps has the Book of Parallax, which contains everything every Sinestro Corpsman has ever done or will do in the name of causing fear.
Later on we see the Book of the Black, penned in the tainted black tears of the undead Guardian Scar.
Knights of the Dinner Table lampshades this while the knights are playing Scream of Kachoolu (the webcomic strips, bound in Tales from the Vault 5): Brian warns everyone to burn all books they find. This is further compounded by the fact that the last campaign ended messily with Bob's character reading a traveler's guide to Boise.
In the Star Wars: Dark Empire comics, the resurrected Emperor Palpatine has written two and is working on a third. They were a kind of combination of Necronomicon and Mein Kampf. The Dark Empire series itself is referred to on occasion as "The Dune Sea Scrolls."
The two completed volumes of the originally intended several-hundred-volume set, to in turn be titled the Dark Side Compendium, were The Book of Anger and The Weakness of Inferiors. The third almost-completed tome was to be titled The Creation of Monsters. In the audio drama Luke comes across tapes of The Book of Anger and finds them horrifically compelling. Just listening to them makes him feel cold and perceive the world as getting darker. It takes an effort of the Force to wrench himself away, and even then he wants to study them.
The My Little Pony G1 Comics contains The Book of Horrors, an ancient tome kept locked away in Majesty's Secret Room in Dream Castle. In the comic story Ponyland in Danger it is consulted by Majesty and Gypsy after they both see ominous indications of an ancient evil approaching in the form of a red cloud.
In the Jackie Chan Adventures fic Queen Of All Oni, Jade is searching for the Teachings of Eternal Shadow (a series of three tablets with the Black Magic of the Shadowkhan/Oni on them) so she can increase her own power and keep Jackie and the other heroes from capturing her.
In the Harry Potter fic Inter Vivos, Draco's mother gave him a book that contained "a great deal of Dark Arts knowledge—spells, but also rituals, potions, and many other things, willed into the book by its possessors". When asked a question, it would shift into a book about whatever the subject might be - provided you asked it the right questions.
The "Black Book" in Fallout: Equestria. It contains dark, necromantic zebra magic designed to conjure flesh eating mega-spells and other nastiness
Luna becomes Nightmare Moon by reading an unnamed book about dark magic in Whispers.
Parodied in the Reading Rainbowverse by the shadowbolts book. While it can add and remove itself from the library catalog, the most terrifying thing it does is draw a dick on Lightning Dust's head.
In Altered Histories Circe was a necromancer who created her own version of the Necronomicon, made of skin flayed from the backs of a thousand men and capable of containing a thousand souls.
The Mummy 1999 had the Book of the Dead, which unleashed the title monster upon the world, as well as its good cousin, which stripped him of his undead immortality and made him mortal.
The plot of the movie The Ninth Gate (based on The Club Dumas, above) revolves around a book called The Nine Gates of the Kingdom of Shadows. In the movie it was an adaptation of an earlier work supposedly written by the Devil himself and contained clues on how to summon him in person.
In Merlin's Shop of Mystical Wonders, Merlin, of all people, gives one of these to a snobby critic, of all people, to try to persuade him that magic is real. As a result, the critic summons a demon, sets fire to a cat, almost crushes himself and eventually manages to provide his wife with the baby she desires by, in a bizarre kind of "reverse incest", turns himself from her husband into her son. Naturally, Merlin thinks this is a jolly delightful jape.
The Lifetime (of all things) movie Devil's Diary references a book found in a graveyard, planted there by a lightning strike. Anything negative you write in the book will come true.
Italian director Lucio Fulci used two. City of the Living Dead had the Book of Enoch (an actual text used in the Ethiopian Orhtodox Church, though it probably doesn't really open the gates of Hell), and The Beyond has the Book of Eibon, which has first written about by Clark Ashton Smith, and used in Lovecraft's "The Haunter Of The Dark, "Dreams in the Witch-House," and "The Shadow Out of Time."
The witches' Spell Book in Hocus Pocus is not only evilly made (bound in human skin, written in blood, etc), and full of horrific incantations, but is actually intelligent and capable of serving its owners' desires.
Big Tits Zombie also features a version of the Necronomicon, which summons and controls zombies.
The Cabin in the Woods kicks off its serious horror elements with the reliable Latin incantation from a spooky old book.
In Warlock, the Grand Grimoire is a Satanic book broken up long ago. When brought together it reveals the hidden name of God, which if said backwards will undo all that he created and destroy the world.
H.P. Lovecraft's Necronomicon is the Trope Codifier. In addition to its cameos and parodies in all sorts of movies, books and TV shows, almost all modern instances of the trope owe something to it. The name is so ingrained in Western culture that many people think the book is real. To a degree this is helped by several companies printing versions of the ''Necronomicon'' (The "My first Necronomicon", a guide to the Cthulhu mythos for children, is done in soft felt.)
Also note that the myth that there is a "real" Necronomicon was helped by numerous pranks carried out back when there were library card catalogs, rather than electronic databases. Specifically, some smartass would create a fake card for the Necronomicon which was always checked out to one "A. Alhazred" (Abdul Alhazred being the fictional author of the book). In addition, during the 1980s, several instructional guides on how to tell if your kid is involved in Satanism suggested asking if they had ever read the Necronomicon.
It's mentioned briefly in Wayfarer. It is said that memorizing verses from it and intense training allows an occult student to pierce the veil which angels and demons hide from humanity.
The Necronomicon is mentioned in the Global Level section of Unknown Armies as a possible source of overwhelming magical power. This is subverted by the fact that those who get the most out of it are Bibliomancers, who gain power by acquiring rare books.
Several books called the The Necronomicon have been published, including:
A collection of short stories about the fictional Necronomicon by H.P. Lovecraft and other writers.
At least two books purporting to be the "real" Necronomicon, which contains a hodgepodge of Sumerian mythology, Hermetic lore, Kabbalah and other mystical writings. In no way do these stories relate to Lovecraft's works, however.
One written by Donald Tyson that details the 'wanderings of Alhazred', and so would be closer to Lovecraft's original idea.
At least one collection of Lovecraft's writings.
The Necronomicon is not the only book of dark lore that appears in Lovecraft's mythos. Some of the others include De Vermis Mysteriis, Liber Ivonis (The Book of Eibon), Cultes des Goules and Die Unsprechliche Kulten (which Lovecraft thought was German for "unspeakable cults", but actually closer to "unpronounceable". Given the names of the Great Old Ones, it's probably more appropriate that way.)
De Vermis Mysteriis has an important role in Stephen King's short story Jerusalem's Lot, a homage to Lovecraft. Necronomicon briefly appears in another short story, I Know What You Need.
Parodying the Necronomicon, is the Necrotelecomnicon (translated as "On communing with the deceased", or "the Phonebook of the Dead"). Supposedly, reading it would drive a man insane, which suits the purposes of the Librarian just fine (he's an orangutan, and thus not a "man").
The books (Equal Rites in particular) even recount an unfortunate case of a mage who tried to read the Necrotelecomnicon, and as a result he was never seen again, and the book became several pages thicker...
The Necrotelicomnicon also appears in the Library of Dream in Neil Gaiman's The Sandman, under its alternate title, the Liber Paginarum Fulvarum (which is Dog Latin for "The Book of the Yellow Pages"). It also makes an appearance in Good Omens (which Terry and Neil wrote together).
The Octavo - the book containing the eight most powerful spells, left behind on the Disc by its creator. (When Rincewind "accidentally" read the book, one of the spells got stuck in his head; this left him unable to learn any other spells [even after he got rid of it] - and was responsible for much of the plot of the first two books.)
And then there's the footnote about how, like Oxford's Bodleian Library, Unseen University's Library has the books chained to the shelves. The difference is that in the Bodleian that's to stop the students damaging the books, while at UU it's...the other way around.
UU also has several volumes of sex magic, one of which must be kept in a room full of ice. Humans can't read them without being driven a very specific type of mad, but the librarian can, because he's an Orangutan, and simply gets unusual feelings about fruit for a while.
The Bonfire of the Witches, written on behalf of the Cunning Man, is so full of his hatred of witches that a copy of it allows a curse ineptly attempted against a witch to work simply by being in its proximity, and later almost allows said creature to manifest into the world through its pages before it's pressed shut very decisively.
Robert W. Chambers' The King in Yellow stories feature the eponymous play which simultaneously enlightens and drives mad anyone who reads it all. (Presumably a production would be impossible to stage.) Only a few brief excerpts, not enough to clearly indicate the plot or subject matter, are ever given. Likewise, the Yellow Sign is never actually described. Chambers' stories predated Lovecraft's Cthulhu Mythos stories and Lovecraft cited them as an inspiration.
A similar work in the Cthulhu Mythos, the Massa di Requiem par Shuggay. is an "opera" that is impossible to perform. Why? If the performance isn't interrupted, Azathoth is summoned midway through the second act. This would lead to everyone going mad or the world ending.
The Dictionary of the Khazars, as described in the lexicon novel of the same name, was printed in a poisonous ink. Remarkably, this ink causes convulsions, pain, and eventual death not from licking or eating the pages, but from reading them, and death would always strike at a particular point on the ninth page.
One might argue that the Book of the Dead in the Undead and ______ books by Mary Janice Davidson is a Tome of Eldritch Lore, as it can only be read for a page or two at a time before it starts to mess with your head. Though given that it gives instructions and prophecies for Queen Betsy's entire reign (whether or not it has more unpleasant spells and such isn't mentioned), it is also a Great Big Book of Everything as well.
The vampire novel, The Historian has one of these which has the effect of attracting Vlad Dracula and his minions to those who find a copy. This is made creeper by the fact that the novel actually looks like the Tome of Eldritch Lore described within.
The book The Club Dumas by Arturo Pérez-Reverté reproduces the nine illustrations that provide the clues to invoke the devil in the tome of eldritch lore (De Umbrarum Regni Novem Portis — everything occult sounds better in Latin), repeated each time the protagonist finds one of the three surviving copies of the Novem Portis, as each one has a subtly different set of illustrations. There is a Twist Ending that hinges on these differences. It is little surprising that these illustrations are supposedly reprinted from the fabled Delomelanicon, or Invocation of Darkness.
The Malus Codicium, from the Warhammer 40,000: Eisenhorn series of novels, is such a book, as it contains many scriptures on daemon summoning, binding etc. The protagonist (an Inquisitor perfectly used to dealing with such artifacts) finds this book particularly creepy, as unlike lesser books encountered, it gives off no sinister aura. It's just like any other book...that helps you bind daemons.
The Necroteuch from the first book is a lesser example, it is the entire focus of the book but what exactly it does is never stated, and it emits an aura of incredible evil so it is a bit of a no-brainer what to do with it. ( After you've tricked a Chaos Space Marine into picking it up. And taken advantage of its effects to kill the Marine.)
In the Whateley Universe, one of the main characters, Sara Waite, is a young Eldritch Abomination. She owns shelves full of these, and considers them ideal casual reading material. As long as she can remind them not to eat her friends.
The Whateley library also has a restricted section of these. And a REALLY restricted section of the worse ones. Note, however, that Sara's are the ones that the library doesn't dare touch.
And then there's horror novelist Michael Waite's best-seller Incongruity, which is really The First Book Of Kellith. The relationship between Michael Waite and Sara Waite is... complicated.
The Old Kingdom trilogy features The Book of the Dead, a green leather-bound book that's different each time it's read and shows a certain disconcerting independence of movement (ie, it knows where it needs to go and will follow along with someone headed in that direction, with or without their cooperation). It can only be opened by a necromancer, and closed by an uncorrupted Charter mage - that is, the Abhorsen and their successor. Normal people find it exudes an aura of deathly chill and utter terror. It's not actively malevolent, though, since it's kind enough to ensure the reader doesn't remember the more horrifying sections until they really really need to.
In the second book of the trilogy, Lirael takes on a job working in the Great Library of the Clayr, which is a bit more like a museum. The books (and "exhibits") range from the prosaic to works of great magic, which are kept under lock and key. This has the unfortunate side-effect that if one of said exhibits gets loose somehow, the person responsible has to find a sneaky way of getting at highly protected books if she wants to have any chance at all of stuffing it back into its can.
In the young adult horror anthology Still More Scary Stories For Sleepovers, the short story "Night of the Ki-Khwan" has an example. The protagonist's scholar mother brings home a collection of texts that describe Native American rituals. One of these rituals provides instructions on summoning the titular Ki-Khwan, who are essentially Native American werewolves. The protagonist and his friends, being young and foolish boys, decide to give some of the rituals a shot late at night in the woods for a thrill. To their horror, they succeed in summoning the man-beasts. Just when it seems like they can keep their campfire going long enough to keep the creatures at bay, a raindance they performed earlier kicks in, putting the fire out.
In the guide book How To Be A Villain, its guide to weapons contains books of evil, which more or less fit this trope perfectly.
John Barnes's One for the Morning Glory features Highly Unpleasant Things It Is Sometimes Necessary To Know and worse, Things That Are Not Good To Know At All.
Du Svardenvyrd (The Weird of the Swords) in Tad Williams' Memory, Sorrow, and Thorn trilogy is a perfectly straight example of this trope. Written by a mad prophet, it causes mortals who read it to Go Mad from the Revelation, and it is eventually revealed that the book is basically an instruction manual for summoning the undead Storm King back into the world. Notable in that the book doesn't have any inherent mystical power, but the secrets it reveals are too much for a sane mind to accept.
The Book Bound in Pale Leather in P.C. Hodgell's Chronicles of the Kencyrath books works a lot like this, even though it was given to the Kencyr people by their God. It's not exactly nice, and neither is the book; reading too much of it can drive you mad or kill you, and the Master Runes inside are highly dangerous to use. Oh, and that leather? Human skin, and the Book appears to be alive; dropping it gives it bruises.
This raises an obvious question: how can dried, tanned hide get bruises?!
No one said it's dried or tanned...
The Shannara Series by Terry Brooks has The Ildatch, an Artifact of Doom dating back to the war between the good Fae and the Demons. Filled with dark magics, it corrupted the rebel Druid Brona into becoming The Warlock Lord, transformed his followers into the Skull Bearers, and later transforms a new group of people into the Mord Wraiths. Destroying it serves as the main plot in The Wishsong Of Shannara. Unbeknownst to all, the book is alive, reasoning, and the Big Bad of the entire trilogy. It nearly turns Brin, the main character, into a monster, before her brother brings her to her senses, enabling its destruction.
In The Cassini Division (a Fall Revolution book by Ken Mac Leod) two characters peruse a market stall selling old books. One tome, Home Workshop Nanotech by a "Dr. Frank N Stein" published some 250 years before the events of the book explained in straightforward terms how to make replicating nanotech using a simple computer, some household chemicals and a tunnelling electron microscope. Sci-fi to be sure; but a mysterious ancient book containing world-shattering knowledge of things man was not meant to meddle with? Sounds pretty eldritch to me.
In The Dresden Files book Dead Beat, The Word Of Kemmler is a book written by the necromancer Kemmler, a major Big Bad who was responsible for a whole mess of atrocities and other badness throughout history, up to and includingWorld War One. Yes, all of it.
Dead Beat also features Der Lied der Erlking, a collection of poetry, art, and prose dedicated to the Erlking, head of The Wild Hunt. Amongst all that poetry is a summoning rite meant to bring the Erlking and the Hunt into the world.
Otherwise subverted, though; the White Council actually encourages the spread of books of dark rituals, since they only have a limited amount of power to go around and mass-publications tend to dilute them into uselessness.
Except in some cases, as Thomas tells us, that perfectly sensible strategy backfires when just the knowledge that the rituals exist, and therefore so does the thing they're meant to summon, is enough to keep the thing in question on this plane of existence.
The dark Book (The Book Which is Not Named) in Diane Duane's Young Wizards series.
Arguably the bright Book (Naming of Lights or The Book of Night with Moon) has the same potential... reading from either book is not something you do lightly.
The short story El Libro de Arena ("The Book of Sand), by Jorge Luis Borges, contains a version of one of these. The bibliophile protagonist trades a priceless 14th-century Bible for a mysterious book in an unknown language that has no beginning, no end, pages that are out of order, and never allows the reader to see the same page twice (it is implied that the number of pages is infinite). Over time, he loses what few friends he actually had, and spends his every waking minute fanatically obsessing over a book he cannot read, copying pages and illustrations before they vanish forever. Unlike most such stories, this one appears to end relatively well- the protagonist recognizes the evil of the book, and disposes of it in a place where neither he nor anyone else will likely ever find it by tucking it into a random, dusty shelf among the National Library's 900,000 books (he first considered burning it, but feared that the burning of an infinite book might be infinite itself and cover the world with smoke). It seems to be implied that he was better off with his good old-fashioned Bibles.
The Grimmerie from the novel of Wicked is implied to be one of these, but no Ozian can actually read the thing. Elphaba can make out bits and pieces, but that's because she turns out to be only half-Ozian. It's also revealed that the Wizard's entire despotic reign is a mere Evil Plan to get his hands on it!
Harry Potter has passing references to these, but they are apparently so common in the wizarding world that the only precautions taken with them is putting them in the restricted section of the school library, rather than the main section. Even though an example of one of these books screams when it is opened for some unfathomable reason...
And there are more horrific versions of this trope in the Potter Verse. The Monster Book of Monsters actually tries to bite its readers. There's the ones Ron warns Harry about: ones that burn people's eyes out, ones that make them speak in limericks for the rest of their lives, or ones that the reader can never, ever stop reading. There's also homemade ones, like the graffitied copy of Advanced Potion-Making, which contains various spells and other magical advice on a higher level than the average student should deal with, written into the margins by Severus Snape. However, those are paltry compared to TomRiddle'sdiary.
Not to mention Secrets of The Darkest Art which was filled with spells so horrible that Hermione treated it like a dead animal.
G. K. Chesterton subverted this trope in The Blast From The Book. The whole thing is an elaborate practical joke.
Thoroughly deconstructed and parodied in R.A. Wilson'sThe Masks of Illuminati, where a number of people are apparently mailed copies of a book that after only slightest glance sends them to suicidal mania, after first thoroughly destroying the volume. As it turns out, the whole thing was elaborately fabricated for the narrator's benefit. The real kicker? The book was Mother Goose's Rhymes - and it had even been subtly foreshadowed earlier in the story!
I could never endure to seclude myself in a golden tower, and spend the long hours staring into a crystal globe, mumbling over incantations written on serpent's skin in the blood of virgins, poring over musty volumes in forgotten languages.
Several Conan the Barbarian stories mention "The Book of Skelos", an ancient tome of black magic that contains spells for summoning demons.
In Valentin Ivashchenko's Dancing Flame:
The unnamed tome on necromancy, written by the last grand necromancer Yaromor. The book contains pure Black Magic knowledge and a large fraction of Yaromor's power, granting both to the current user. The power also actively searches for new users every few centuries, although Heroic Resolve allows to contain the power without being corrupted. Killing the user grants the world said few centuries of peace, thus forcing a later generation to deal with the next grand necromancer.
Earl Valle's spellbook. Valle is the most powerful and most studious necromancer to ever live - his spellbook contains a few things generally thought impossible for necromancers by the setting's Mutually Exclusive Magic. Valle himself was disgusted by the book's contents, so he just destroyed it.
In Vitalij Zykov's Return series, this trope takes the form of stone tablets rarely found at relic sites of ancient civilizations. The tablets are covered with text in a language older than any humanoid race, including two elven races. It's only known that the tablets contain magic-related information. The protagonist happens to learn said language by Exposition Beam, learns one of the spells and casts it in a magical duel. The resulting damage is considered overkill in comparison to magical carpet bombing by dragon squadrons.
In Strong Spirits, the protagonist's rival in mediumship, Cockcroft, has acquired a famous necromancer's Tome of Eldritch Lore and wants to summon the author's ghost to help him figure out its cryptic contents. Subverted when the ghost is finally contacted and admits he was a charlatan who wrote a fraudulent "spellbook" to impress the rubes.
In Charmed, there is the Grimoire, which is the demon equivalent of the Book of Shadows.
On Buffy the Vampire Slayer, Giles had whole bookcases filled with these. "Xander, don't speak Latin in front of the books."
He used to keep them in the library of the high school. This was lampshaded once, with the principal doing a search of the library and questioning whether it was appropriate to have in a high school library filled with tomes instructing on the uses of dark magic - despite being asked during a period of demonic-inspired moral panic against magic, this was actually quite a reasonable question, considering.
Or maybe some of Giles' friends and associates...persuaded...Snyder to give them back. Or maybe he made him forget the whole thing, and took them back himself. This IS the guy who introduced the freaky-cool ninja dude to his wife, in the fake-evil-Angel-to-fool-Faith episode.
Giles explained in an early episode that he did it because the students never come into the library. It's the perfect place for a Watcher to put a collection of books so no-one will ever read them.
Remember that in a previous episode Giles physically threatened Snyder so he would reinstate Buffy. Besides, the books were probably kept by the anti-supernatural mob and would probably return it to him since it was his "personal collection".
And then at the end of season 6, Willow absorbs all the knowledge from these books and actually does set off to destroy the world.
The finale of Star Trek: Deep Space Nine, of all series, featured one of these. The fact that its pages remained blank until splattered with the blood of a murdered man really should have been a hint that the ritual it was going to be used for was not a good idea.
The Grimoire in Blood Ties is used several times to summon demons. Henry has his own copy, "confiscated" from a bunch of Medieval cultists, and uses it to sabotage summoning rituals.
Power Rangers Lost Galaxy had the Galaxy Book. Tellingly, our heroes found it answering a Distress Call from a ship whose crew had been wiped out be an unnamed monster. It might not be inherently evil, but it has the power to open a portal to the titular Lost Galaxy, a pocket dimension full of deadly space pirates. It also contains the history and location of other creatures and weapons that are nearly as dangerous.
Sleepy Hollow: Episode 4 revolves around the heroes stopping a group of Hessians from retrieving the Lesser Key of Solomon an ancient text capable of opening a portal to Hell and unleashing the 72 demons sealed there by King Solomon.
Dungeons & Dragons has had countless numbers of these over the years and editions. If one is of a magical turn of thought, caution should be taken when putting pen to paper. The most notable and persistent of these tomes is the Book of Vile Darkness, which is so evil that reading it can damage a good person's mind. (The publishers of the game actually produced a sourcebook on evil by this name later on.) The original edition of D&D actually had separate versions of this text for priests and wizards, with the Book of Vile Darkness being the priestly version and the Libram of Ineffable Damnation the wizardly version. A few subversions also exist: the Book of Exalted Deeds, a book of pure goodness (and the Libram of Silver Magic, its wizardly cousin), and the Libram of Gainful Conjuration, which can only be read if you don't side with either good or evil.
All of which are mere cheap knockoffs of the REAL badass book of AD&D, The Codex of the Infinite Planes. How bad is it? For starters, it's the size of a small room. Also, it has infinite pages, literally. Just opening it can reduce you to a small pile of ashes. If you aren't killed, you can use the book to achieve near-perfect power over reality... but if you ever stooge one of the spells within, they'll never find your corpse (assuming you leave one).
The Tome of the Stilled Tongue, sacred to Vecna, deserves its own mention. This is the kind of book which a) can only be safely used by those worshipping an evil lich-god of scheming and dark magic and b) comes with a free human tongue nailed to the front as an example of why you shouldn't blab the secrets of the Maimed God.
A few non-magical tomes of lore have achieved prominence in D&D, including the Black Scrolls of Ahm and the notorious Demonomicon of Iggwilv.
Another is the Codex of Betrayal, which is a collection of four books, each with several dozen chapters, totaling multiple thousands of pages, written by the last follower of the God that was murdered and over thrown by Asmodeus. It chronicles the history of the god, the war in heaven, and the creation of devils, serving a similar function for devils as the Demonomicon of Iggwilv serves for their Chaotic Evil adversaries.
The Book of Keeping is not truly a magical tome, but still a dangerous one. This book contains information on summoning powerful yugoloths, even giving the true names of a few of them. No-one knows who wrote it - given that he would likely be the yugoloths' most hated enemy, he may no longer be alive. At least four copies of the Book exist, although some say as many as seven, and their owners tend to change frequently.
Exalted has numerous examples, but the most infamous might be The Broken-Winged Crane. How bad is it? It isn't even written yet; all the copies that exist are reverse engineered from the perfect version that comes into existence the day the world ends.note It should be noted that time travel is explicitly impossible in the Exalted setting. This has not stopped the imperfect copies from appearing well before the book is written. And seeing as the only canon character to have read the book is implied to have been abducted and mind raped by archdemons, there's a very good chance the book causes it.
As befits its tone, Deadlands has a few of these tucked away in its pages and pages of Splatbooks. The most "Eldritch Lore-y", though, would be the Whateley Family Bible, which—in addition to having the Family Tr...Shrub (don't ask) in the front pages—contains margin notes on how to perform all manner of dark arts. The irony of profaning a Holy Bible is not lost on the misanthropic family. Player Character Whateleys, while assumed to be a moral cut above their NPC brethren (and cousins and uncles, some of which are the same people), can get a "pocket sized" version, which contains less forbidden lore and can cause panic in anyone attempting to translate it...whether they succeed or not!
Mage: The Awakening has numerous books called grimoires, where a mage enscribes all their knowledge of a spell (literally; it leaves their mind forever) so that others can learn it more easily. Needless to say, some grimoires are less than wholesome, including: the book of the life of an Atlantean prophet that turns those who study it enough into a psychic clone of said prophet; a bestiary on Abyssal beings that leads the mage who reads it enough to believe that he's uncovered an important secret and that all his friends have turned on him; and the book that contains both normal spells and spells that draw upon the Abyss but doesn't tell you which are which. Grimoire of Grimoires is an entire sourcebook dedicated to these.
The worst of these are The Final Spell Of Eli Ben-Menachem, The Invsible Codex, and The Prince of 100,000 Leaves. The first is a seemingly-sentient spell that teaches you how to summon reversed forms of Goetia symbolizing reversed Virtues into your enemies' minds, which are actually Abyssal entities who willescape. The second is an Abyssal creature in the form of a Tome of Eldritch Lore, which actually takes that form to lure power-hungry mages so it can eat their souls. The last is an Abyssal entity that takes the form of 100,000 pages detailing a twisted alternate history for the world, which will then proceed to become real— the catch is that it's not fully written or put together.
Interesting subversion: The Ialdabaoth Codex, besides being incredibly hard to spell, seems like it at first, being an Abyssal bestiary that gradually drives its readers to paranoia and the summoning of its contents... except that's the precise opposite of the book's intended function. It's actually a prison for the various Eldritch Abominations it describes (it scours the mind of its new prisoners and writes an entry based on its findings), and the madness is the result of them trying to get out. The writers of the book were actually pretty nice people, and a story hook presented involves reconstructing their Legacy.
While most of them don't literally involve books (and conversely not all book-related cards in the game suffer from this, either), Magic: The Gathering features its share of cards that play on the 'forbidden knowledge' theme by providing access to additional cards for a modest sacrifice in life points or cards already in hand or in play.
With the release of the Innistrad set, based on gothic horror, it has an archetypal example: Grimoire of the Dead, whose playtest name was, in fact, "Necronomicon".
Warhammer 40,000 brings us first the Book Of Lorgar, which helped start the Horus Heresy. Then in true 40k fashion, it goes overboard with the Black Library: an entire extradimensional stronghold full of forbidden lore, guarded by space elf ninja clowns who worship a god that managed to trick other gods into eating each other. Named the Laughing God of course.
Pyramid had an article detailing Clay Bricks of Eldritch Lore which fit pretty much every aspect of this trope (unreadable, evil, drive you crazy) except that they're not actually books (being from before bound books were invented, or from cultures that never did).
The Call of CthulhuRPG has the typical Lovecraft library from the original stories, and a few additions of its own.
And by a few additions we mean an entire sourcebook filled with half to two page descriptions of books both taken from other Mythos sources and invented outright. The major works generally include an Apocalyptic Log hinting at what has happened to characters who came into contact with the book, a history of the book and the explicit effects both skimming and reading it have. Guess what the sourcebook is called...
An expansion book, Warriors of the Apocalypse, includes a Bane character named Tsannik. His human host summoned him using an ill-gotten book of sorcery.
Appropriately, the Necronomicon features as a usable (by Professors only) item in the Munchkin expansion "Munchkin Cthulhu." As do Necronomicon parodies like the Necrocomicon, the Necronookiecon and the Necrotelecom.
Warhammer Fantasy had the Nine Books Of Nagash the Necromancer. The originals were destroyed but there are some copies still lying around.
Games Workshop also released a book called Liber Chaotica (the Book of Chaos), a guide to all things Chaotic in the the Warhammer world, with occasional referances to Warhammer 40k. As a different take on this trope, the writer was not trying to support Chaos, but was ordered by the Cult of Sigmar to compile it to help fight Chaos. Naturally the study of such subjects has a less than stellar effect on his mental health.
In Earthdawn any book about the Horrors can potentially have bad effects on the person who reads it (including the Horrors source book), but probably the straightest example of a Tome of Eldritch Lore is the Book of Scales. According to legend, a group of powerful Horrors captured a dragon and forced it to write a history of the Horrors, using the dragon's own scales as pages and its own blood as ink. The dragon then scattered the scales as far apart as possible to minimize the damage. The Book of Scales allegedly contains valuable information that can be used to battle the Horror, but is so tainted that carrying around a single scale (not even reading it, mind you, just carrying it) will eventually drive a person mad.
The backstory mentions the six Books of Harrow, which tell of the existence and powers of the Horrors. The first man to study them was found dying after ripping out his own eyes and holding them in the fire. Thus far, only one was fully translated; perhaps coincidentally, the Scouring happened a few hundred years later.
A flavor text in the Nobilis Third Edition rulebook says that A Philosophy of Treason, a book detailing the case for serving the Excrucians, has many fake copies that will remove the eyes of any who read and fill their eye sockets with worms. Oh, and the genuine article is almost as bad. Ouch.
The script notes actually call for Martin, the most knowledgable major character on the subject, to react as if given "a handful of glowing plutonium" when he receives the Xarxes. It's just that sort of book.
In addition to the Xarxes, there is also the Oghma Infinium (infinite wisdom) which is bound in skin and is owned by Hermaeus Mora, the daedricprince of fate and forbidden knowledge. Also the Tome of Unlife which creates liches and the book used in Skyrim to learn the master destruction spells may qualify.
The Mysterium Xarxes and Oghma Infinium may be quite eldritch, but if you really want to read something you really shouldn't, try one of the titular Elder Scrolls. The Elder Scrolls are completely irrefutable recordings of history/alternate history; what did happen, what could have happened, what might happen. Even the falsehoods in them are true. Especially the falsehoods. Reading them completely untrained will yield just some weird chart that looks like it has constellations on it, with odd glyphs printed over (or under?) the chart. An incompletely trained reader (knows just enough to hurt themselves) will end up getting something out of it but likely useless, and their eyesight is gone. A well-trained reader can glean much and eventually regain their eyesight... for a finite number of times before their sight is gone for good. The power of the Elder Scrolls is so great, their truths so irrefutable, that not even the machinations of a daedric prince can overcome them; that's how the curse on the Gray Cowl of Nocturnal is broken in the Thieves' Guild quest in The Elder Scrolls IV: Oblivion. In The Elder Scrolls V: Skyrim, you get to read one yourself to gain knowledge of a dragon shout lost to time; it turns out you don't read the scroll, you see events happen as if the scroll was a window to another (possibly alternate) time. Trying to read the scroll outside of the Time-Wound temporarily robs you of vision — and the reason you only suffer that much is because you have the soul of a being that exists partially outside of time, not unlike the Elder Scroll itself. Even the Dragons like Paarthurnax and Alduin himself fear the Elder Scrolls' power. Turns out that they don't just reveal events, they can alter reality as well; with no recourse left, the ancient Nordic heroes who faced Alduin invoked the power of an Elder Scroll to "cast Alduin out of time", postponing his reckoning until the age where Skyrim (the game, not the province) takes place. The residue from that event was the Time-Wound mentioned above.
Also, those who study how the Elder Scrolls actually work go insane with clockwork regularity.
In Dawnguard, you undergo the same ritual Moth Priests go through to be able to read an Elder Scroll after the Moth Priest you rescued goes blind after reading one without the necessary precautions. After reading the Scroll you are none the worse for wear, likely because as the Dragonborn, your Aedricsoul protected you from the normal side-effects.
Dragonborn introduces the Black Books, which are more or less the Oghma Infinitum's little brothers. Reading them teleports you to Apocrypha via black tentacles that comes out of the book, the realm of Hermaeus Mora in search of a new power. Like the rest, it drives most mortals insane (unlike the dragonborn) but grants as much power as the infinium (spell buffs, shout buffs and skill respec).
Fallout 3 has the Krivbeknih and some other unnamed tome, part of a Shout-Out side quest in both the Point Lookout expansion and the original game, respectively.
A couple of optional quests in Fable II have the Normanomicon, the book of the extremely dead. Said quest is a touch underwhelming, as it mostly involves getting the book back from a bunch of undead mooks two bumbling brothers (Max and Sam) have accidentally summoned.
The book returns in Fable III with a more interesting quest line, which involves getting the book for the ghosts of the two brothers from the last game, and one of them going mad with power.
The Gran Grimoire in Final Fantasy's Ivalice Alliance miniseries. In Final Fantasy Tactics Advance, it's a magickal tome that transforms the sleepy town of St. Ivalice into the actual Ivalice. In Vagrant Story, it's not a book per se — every stone in the city of Leá Monde is inscribed with ancient Kildean runes, turning the city into the ultimate codex of magick.
Golden Sun has the "Tomegathericon" an item which allows the party member who equips it to take the "Dark Mage" classes, and grants powers such as attacking with hellfire, summoning demons and raising zombies. Curiously, the tome is given to the party by a benevolent animistic deity, who asks that they safeguard it until the witch doctor of the tribe that worships the deity has matured enough to be worthy of receiving it (witch doctor also being a benevolent role, when not occupied by an irresponsible teenage apprentice). Note that it was actually called Necronomicon in Japanese.
The various magical tomes from Grim Grimoire. With every new "Groundhog Day" Loop cycle Lillet goes through, they become even more powerful, until she's capable of summoning dragons, golems, and arch-demons.
Shadow Hearts has the Emigre Manuscript, a book so evil that it even has skull-shaped pages. Its main selling point is that it contains instructions on how to bring someone Back from the Dead, something attempted in all four games of the series. Unfortunately, most attempts end up as grotesque Eldritch Abominations.
The Pulse Tract and R'lyeh Text count even more so. The Pulse Tract incarnates a god form the soul of the earth, one which very nearly destroyed all of Shanghai and subjected the our hero to The Mother of All Mind Rapes. The R'lyehText however, besides being named after a certain undead city, 'summons a god form beyond the stars' which was described as being as far above humanity as humanity is above insects. Eldritch indeed.
Super Paper Mario has the Dark Prognosticus, which was featured in the header picture. The game's intro states that "The book held frightful secrets not meant for people's eyes." Later in the game, it's discovered that Lord Blumiere was reborn as Nietzsche Wannabe Count Bleck upon first opening the book.
Another book, the Light Prognosticus, was written later. Unlike its darker cousin, this one predicts Mario & Co. stopping the end of everything.
Forbidden Scrollery of the Touhou series is entirely about these books; it's even in the title. Kosuzu Motoori is a human bookseller and lender who collects them and has the magical ability to read them. Most of the relevant ones have youkai sealed inside. Or give birth to youkai by making you think about them. Or are youkai themselves, in book form.
Also, the Grimoire of Alice, which is always sealed up. The one time Alice used the book, she jumped from a 3rd stage boss into a Bonus Boss. However, she hasn't used it since then.
Books of dark magic and eldritch lore appear in Warcraft games. Notable ones include the Book of Medivh, which was used to summon the demon lord Archimonde, the Compendium of Shadows, and Lexicanum Demonica, which is said to contain the name of every demon in existance.
The Book of Condemnation in Suikoden V and Alhazred, the recruitable character who is looking for it.
In Shadow of the Comet, the player gets to read a few pages of the Necronomicon, although he's been warned that it would drive him crazy. (he can't move forwards in the plot without doing so) Apparently, it's safe to read it as long as you don't take it away from the room it was stored in.
"Fragments of the Book of Abdul" and "De Vermis Mysteriis" in the original Alone In The Dark 1992. The first one hurts Carnby, the latter is instant death.
"Legend has it that the mad Arab Al Aksandir Garambel wrote it after he was driven insane by his very first summoning, a terrifying entity known only as Wa'tz'ynn."
In the Call of Cthulhu RPG, all the books are present, from The Book of Eibon to The Necronomicon. Books will give you knowledge of the occult, but also cause permanent Sanity loss.
In the Lovecraftian-style Interactive Fiction game Anchorhead, there are (appropriately) several evil artifacts, including a Tome of Eldritch Lore. Tip for players: don't read it.
In Tales of Phantasia, the summoner Claus main weapons are books, including the Necronomicon, Liber Ivonis, Requiem (for Shaggai), The King in Yellow, Celaeno fragments, and pretty much any other fictional grimoire from the Cthulhu Mythos. The GBA version has alternative spellings (or poor translations) of said books. Also, these books apparently weigh a ton, since Claus can use them to smack around monsters.
In Final Fantasy Legend III the wizard Shar can use the Tablet to free the people of Pureland from the Masters power. Since the whole game is a Shout-Out to the Cthulu mythos its most likely the Necronomicon. In the original Japanese it's a "Goblin corpse".
In a nod to the D&D examples listed above, Planescape: Torment has a book called the Grimoire of Pestilential Thought. Not only will it offer to teach spells in exchange for the main character doing increasingly awful deeds, it can also offer 'advice' which has a very good chance of making the main character more evil just from hearing it.
The Fire Emblem series has a few of these— in fact there's an entire school of magic that is dedicated to using the magic in these kind of tomes, the aptly named "Dark" magic (Although, because Dark Is Not Evil, but many think it is, some good dark-wielders call it "Elder magic".) Effects from delving deep into the dark arts often includes insanity and corruption— whereas the spells themselves are known for having interesting effects such as; Stealing one's life force (Nosferatu), Summoning a horde of voracious insects (Swarm), Exposing someone's soul to the torment of hell (Hell), making someone explode in a shower of blood (Balberith)... but the most true to the form of this trope would be the tome of Loputous in FE 4— a book containing the power of a Child-Eating Dark God. Upon reading it, Prince Yurius went completely insane, murdered his mother (he tried to kill his adorablesister too, but she was warped away before he could)... it's effect: Halving the stats of anyone who challenges the wielder, unless said opponent is wielding the tome's opposite number, Naga)
Jets'n'Guns Gold Edition features the Necrofilicon, a book with such horrible grammar, reading any part of it out loud will awaken the dead in the immediate area.
In Persona 2, the In-Laqetti. Somewhat deconstructed in which the entire thing's a sham-but the rumors sparked by its release aren't, which jibe with Sumaru City's powers to bring all of them into reality.
In the Mage Towers level of Thief: The Dark Project, some documents mention a rogue necromancer's attempt to locate the dreaded "Book of Ash". As it turns out, this book can in fact be found in the sequel. From what the player can see it contains rituals in Lovecraft-speak, and has a rather nasty fate in store for anyone who reads it.
Dungeon Crawl has three: the Grand Grimoire, the Necronomicon, and the Book of Annihilations, all of which can do nasty stuff to inexperienced casters if they try to read them.
The eponymous Book of Shadows in the second Corpse Party game. May or may not be sentient.
The Datasphere of 8-Bit Theater. What else it can do is a little vague (BM looked into it once as RM mentioned "knockers" and apparently the experience was "very soft"), but when Red Mage took a long look at it without interruption, he gained the knowledge of how to destroy anything that could ever exist. Sarda powered on the four orbs apparently couldn't exist, so what appeared to be a masterful plan turned into a Batman Gambit that nearly ended the world. Only a nine-year-old brick joke saved the world from Chaos.
She refused to use it as her Weapon of Choice because it sounded like a bad idea. (1) However, that didn't prevent her from using it in alchemy to make the Thorns of Oglogoth, which she does use as weapons even though no sane person should.
The Necronomicon and The King in Yellow exist in the Whateley Universe, as does The First Book of the Kellith. Unfortunately for the future of said universe, that particular book was actually published as a horror novel, and it was a best seller.
The Simpsons parodied it. In the first Treehouse of Horror episode, one segment features an adaptation of Edgar Allen Poe's "The Raven". When the line about reading the quaint and curious volume of forgotten lore comes around, we find Homer reading a book titled "Forgotten Lore, Volume III"
In another episode, Lisa is cleaning out the garage and finds a thick leather bound book. She begins to read the Latin and behind her, a demon begins to form. However the horror is foiled when she tosses the book aside in favor of Mad Libs.
And again in Halloween special III where Bart and Lisa find a book in the library's "Occult section". Bart attempts to bring back their dead cat Snowball but end up raising the dead in the human cemetery, which was right next to the pet cemetery.
Also the members of Springfield's Republican Party read from the Necronomicon.
During the trial episode of season 1 of The Venture Bros., Dr. Orpheus asks the bailiff to swear him in with his own book. A book that bears a suspicious resemblance to the Necronomicon. As the book snarls at the bailiff, Dr. Orpheus warns: "Careful, he's a nibbler!"
There's also the Orpheus' tome that Dean reads from in the ambiguously canon Christmas special episode. While perusing it for Christmas stories, Dean accidentally summons The Krampus. Orpheus was also known to read from it while baking gingerbread cookies.
Titanium Chef from Sushi Pack uses recipes from "The Book of Chum Chop: Ancient Recipes for Chaos and Mayhem" to perpetrate his villainy. This includes creating perfect (but emotionless) doppelgangers, opening a warp to a parallel universe, and cooking up a batch of shoeshine that makes anyone who uses it feel cold even though they're not (It Was Evil In Context).
Subverted in an Earthworm Jim episode "The Book of Doom," in which the "most evil book in the universe" is revealed to be Fuzzy Wuzzy's Funny Animal Pop-Up Book. Doubly subverted in that a few copies turned out to have accidentally been printed with a page explaining how to destroy the universe, just after the pudgy-wudgy hippo.
He-Man and the Masters of the Universe (1983) and She-Ra: Princess of Power had a few of these, including a spellbook that would summon Daimar the Demon, in the He-man episode Daimar The Demon, and the Ancients' Book of Spells in A Bird In The Hand. In the She-ra series, Shadow Weaver got ahold of the Eldritch Book of Spells in The Eldritch Mist. Then Madam Razz had to locate the Nameless Glowing Book to find a spell to get She-ra out of the Sixth Dimension in Three Courageous Hearts.
The Grimoire of Honorius was supposedly written by Pope Honorius III; he was evidently so holy that he got bored fighting off the temptation of the mundane world and took to summoning demons solely to turn down their offers.
The Sixth and Seventh Books of Moses is a usually single-volume Spell Book which purports to be Older Than Dirt. It was considered by Kurt E. Koch, a German Lutheran minister, to be an Artifact of Doom because one page in the volume maintains (he claimed) that whoever owns the volume belongs to Satan. In other words, if it's on your bookshelf, Satan can do with you whatever he wishes. He maintained, therefore, all copies must be destroyed.
Ancient Egypt had the Book Of Going Forth By Day — popularly known as The Book Of The Dead. The book was a collection of various spells for different Pharaohs, printed on the walls of their tombs. It was essentially a collection of "prayers," or spells, but due to this, the spells were almost entirely unique to the individual. Some spells were very similar to each other, and some Pharaohs even had the exact same spells as others, but the spells were not intended to be used by anyone except the Pharaohs themselves. The spells were usually various forms of magical protection against demons in the underworld, or incantations to help one reach paradise.
The Thousand And One Nights aka Arabian Nights is said to drive to madness anyone who reads the entire work. It's online at Project Gutenberg for anyone who's curious enough to try it. 
Worth noting: the Arabian Nights contain copious amounts of sex. Well, what did you expect from stories a woman reportedly told to her husband in bed at night?
According to the framing story, she's technically telling the stories to her little sister who was hiding under the bed while she had sex with her husband and jumps up afterwards to ask for stories. (The framing story paints the entire thing as a long-term plan to heal her husband of the peculiar insanity that caused him to murder all his previous wives.)
The Malleus Maleficarum definitely qualifies. It's a book written by fifteenth-century witch-hunters to record the depraved practices allegedly practiced by the diabolical witches, and the equally cruel tortures that were visited on those who were suspected of being witches. However, its recommendation by the reigning Pope was forged: he denounced the Malleus Maleficarium as heretical. While the Pope had inaugurated witchcraft trials in Catholic areas, overturning the 9th century canon that said believing in witchcraft was heretical, what the authors of Malleus were doing was completely outside the laws and beliefs of the Church.
One of the books's two "authors" had his name used on it without permission (and boy was he mad when he found out) by the guy who actually wrote it, a German monk so hopelessly obsessed with demon rape that he got tossed from every monastery he got sent to after he drove the monks up the wall by talking nonstop about said demon rape.
Two particularly famous examples, the Voynich Manuscript and the Codex Seraphinianus, are often confused with each other because they're superficially very similar: Both are encyclopedias written in an unknown language, peppered with bizarre illustrations of otherworldly biology. The Codex is a "work of art" made in the 70s, but the Voynich Manuscript dates from sometime in the 14th century, is written in what appears to be a real (but unknown) language, and is filled with illustrations that just make it more confusing.
One of the most common and accepted theories is that it was made by the known alchemist and con-man John Dee. He sold it to the Czech King Rudolf II for 600 gold coins. The King was a famous patron of anything somehow resembling sciences, and had many of the best known alchemists and spiritists of the day in his pay. While this would make the book a forgery of a Tome of Eldritch Lore, it would still be an authentic 16th century forgery.
The illustration in the Voynich Manuscript are definitely not outlandish and the book resembles any other early naturalist treatise. The text, however, has not been yer deciphered.
The form of the Manuscript is a very standard one for a 16th century treatise on the medicinal uses of plants. The actual plant illustrations, however, show plants that typically have the roots of one plant, the stems and leaves of a second, and the flowers of a third. If it is a fabrication, however, the text was done in a diabolically clever manner. Modern computer analysis shows that statistically the text is entirely consistent with a phonetically written language, despite the fact that the lack of computing machines capable of performing such analyses in the time the book is first definitively known to exist would make faking such features extremely difficult.
The US Army field manual TM 31-210, "Improvised Munitions Handbook", is probably the best mundane equivalent. Won't summon demons, but almost any use will summon FBI agents. Unlike the other books in this list, Army field manuals are available on Amazon.
Adolf Hitler's Mein Kampf has started to become something like this. It isn't actually banned in Germany, but the copyright is owned by the government of the state Bavaria which never allowed any prints since the end of World War II. Supposedly it's a book so dangerous that it can turn normal people, or at least easily influenced teens into fascist racists, so it must never be allowed to get back into circulation again. There are some attempts now to publish the content with annotations by historians to remove the myth from the book and showcase that it's really just incoherent rambling, which seems preferable to letting curious people just dig up the text on the internet on sites with dubious character.
This only applies to Germany and a few other countries where it is either banned or very difficult to get. In many countries it can be readily found in bookstores, which rather diminishes this effect. In fact, it can even be ordered over Amazon.com.
Arguably, the Football (a briefcase containing nuclear missile launch codes, always within easy reach of the President of the United States), which in the wrong hands probably is capable of bringing about The End of the World as We Know It.
And very concerning, after the assassination attempt on President Regan, it was actually lost for a time and a new copy of the codes had to be located for then-Acting President Bush.
The Mystery of the Cathedrals. Written by an alchemist in the 1920's using the pen name Fulcanelli, the work makes the case that the Cathedrals of Europe, as built by freemasons, are in fact stone manuals outlining the "Great Work" of alchemy. The work was followed by a sequel, The Dwellings of the Philosphers. A third manuscript was intended for publication, however, it was recalled by the author at the last minute due to its secrets being too dangerous for public consumption. Interestingly, the CIA had an extensive file on Fulcanelli and conducted a massive search for him in the years following WW2.
The Catcher in the Rye. Most famously found in the possession of Mark David Chapman, the man who assassinated John Lennon who claimed inspiration for the act came from the book. The book has been further linked to other famous murderers and assassins. Conspiracy theorists have claimed that the book is somehow used by shadowy government forces as a trigger for sleeper assassins like in The Manchurian Candidate, something touched upon in several movies such as the Mel Gibson thriller Conspiracy Theory.
L. Ron Hubbard claimed to have written a manuscript that caused people to go insane or commit suicide. Early Scientologists once sold copies of this manuscript for $1500.
A lot of Scientology is filled with this same principle. Take for example, the infamous Xenu storynote 75,000,000 years ago, Xenu was the head of a Galactic Confederation of Planets. The confederation suffered from overpopulation, so he abducted large numbers of beings, froze them, and flew them to Earth, where he arranged them around the bases of volcanoes and blew them up with hydrogen bombs. He then captured the thetans (souls) of these beings and brainwashed them with images of all the religious imagery that exists today, including the entire story of Christ. Upon release, these thetans clumped together and attached themselves to our ancestors, and through various incarnations they remain attached to us today.; if you try to cure yourself of its effects, it's supposed to trigger a sudden, fatal onset of pneumonia.
In addition to being one of William Shakespeare's darkest and eeriest plays, Macbeth is supposedly cursed. An unusually high numbers of accidents and deaths have occurred during productions of the play, which is why actors avoid referring to the play by name, calling it "the Scottish play" instead.
The Grimorium Verum, which is an occult manual generally though to be written during the 18th century, though the authorship purports to be from the early 16th century, and derived from King Solomon. Interestingly, it nicely averts Fantasy Gun Control.